Vacuum cleaner



m. 26, 1937. J, c, CLASON 2,096,883

VACUUM CLEANER Filed July 6, 1934 VACUUM QuA/vr/ry 0F 4/? FLOW fig-ATO NEY Patented Oct. 26, 1 937 Jan Carl Mason, is

' OFFICE 1- Sweden, aangnor to Electrolux Corporation, ver, Deb, a corporation of Delaware Application My invention relates to vacuum cleaners and the method of operation thereof.

The air flow producing device of a vacuum cleaner, during the ordinary use of the cleaner, is called upon to circulate varying quantities of air. These variations in quantity may be caused by several factors acting either singly or in combination. For instance, if the cleaning tool or nozzle is attached directly to the cleaner unit there is 19 less resistance ofiered to the flow of air than if.

the nozzle is connected to the unit by an intervening length of hose, and consequently, other factors being the same, the quantity of air circulated. in the first case is greater than in the second. 35 Likewise, a large nozzle oflers less resistance to the flow of air than does a small one. Also, the nature of the surface being cleaned has an eflect on the resistance. A hardwood floor, for irrstance, has less sealing eflect on the cleaning nozzle, and hence ofiers less resistance to air flow, than does a heavy carpet. A loosely woven rug has less sealing eiiect' than doesa rug with a close weave. Whenever the resistance to the flow of air is small, the reduction in pressure caused 2 by the fan or other air flow producing means need be but comparatively small, while when the resistance is large the reduction should be comparatively great in order to draw the-air in against the high resistance.

One of the objects of the invention is to provide an air flow producing device which will produce a large air flow with a small reduction of pressure and, when the air flow is reduced, will cause a large drop in pressure while operating with high efllciency under both of these conditions.

Further objects and advantages of my invention will be apparent fromthe following description considered in connection with the accompanying drawing which forms a part of this speciflcation and of which:

Fig. l is a cross sectional view of a vacuum cleaner including one embodiment of my invention;

Fig. 2 is a cross sectional view of a portion of the vacuum cleaner including another embodiment of my invention; and

Fig. 3 is a performance curve of a vacuum cleaner including either of the embodiments.

Reference character Ill designates a preferably cylindrical air-tight casing. A ring Ii is secured to one end of easing ll. A bell-shaped member I! is adapted to be clamped to ring H by means of suitable spring clips l3, and is provided with,

a central threaded inlet opening ll. A coupling member I is adapted to be screwed into opening July 6, 1934, Serial No. 33%,99?

-:'=m.:;. July 19, 1933 l5 and also to receive one end of a hose it. The other end of the. hose may be connected to a cleaning nozzle ii. A dust bag l8, made of material which is pervious with respect to air but prevents the passage therethrough of dust, has its open endsecured to a ring it, which is formed with an outwardly extending flange 2B. Flange 20 is provided with a packing member of rubber or other suitable material, and is clamped between ring H and member i2. i 1

- The rear end of casing 10 is provided with a ring 2! to which is secured by means oi bolts 22 a motor supporting ring 23. A motor 23 is suitably supported within ring 23, as by means of lugs 25 on the ring which engage springs 28 supported 15 in lugs 21 formed on the motor housing. The

motor is thus resiliently supported.

A member 28 having a perforated wall 28a encloses the rear end of motor 24 and is secured to ring 23 by boltsdab. A cap member 2a fits over an the cylindrical part ofmember 2B and may be removably held in place by spring clips similar to spring clips I 3. Cap 29 is provided with an outlet opening 30,'in which are arranged inclined vanes 3! for directing the air discharged therethrough upwardly and away from the surface on which the cleaner is supported. Arranged between member 28 and the outlet 30 in cap 29 is a filter 32 which fits within cap 29.

A handle 33 for carrying the cleaner is secured to the upper part thereof. One end of the handle is fastened within a standard 34 which also serves to house an electric switch 35 and contact members 36. The cleaner unit is supported horizontally above the horizontal surface by means of a 1 pair of runners t! which are secured to rings II and 2| at opposite ends of the casing Ill.

A fan rotor so is mounted on the shaft of motor 26, so as to rotate therewith. Rotor 38 includes a circular disc 38a secured to the motor shaft. A plurality of curved blades 38b are carried by disc 380, the right hand edges, as viewed in Fig. 1, of the blades being secured to the disc. The opposite edges oi the blades are secured to a disc .380 formed witha central circular opening, A g 3 fan housing comprising a cylindrical portion 39 and an end wall 401s supported on ring 23 and encloses the rotor 38. Wall 40 is formed with a central opening 4| which, under certain conditions, is closed by a valve member 42. Valve 5 member 42 comprises a circular disc supported by a hub 43 which is slidably mounted on a pin 1 ll. The pin It is rigidly secured to an arm ll which extends across opening 41. A spring. surrounds pin M and has one endbearin'g against hub 48 and the other end against a head" on the pin. Spring 48 therefore. tends to force the valve member 42 to a closed position. Secured within the forward part of the fan housing is an inner housing 48 which forms an annular passage 49 between itself and the fan housing. The forward end of inner housing 48 is supported by end wall 48, while the other end of the housing is provided with a wall 58 having'a central opening 5| therethrough. Opening 5| constitutes an inlet for the fan rotor 38.

Inner'housing 48 is provided with one or more openings in which are secured suction inducing nozzles 52 each having a central passageway 52a formed in the shape of a Venturi tube. 'Nozzles 52 are preferably arranged .so as to have their inner ends directed toward the fan inlet opening 5|. End wall is provided with openings in alignment with nozzles 52, into which openings are secured induced suction nozzles 53, the inner ends of which terminate within the most constricted part of the Venturi shaped passages 52a in nozzles 52. The outer diameter of the inner ends of nozzles 52 is slightly less than the diameter of said constricted portions, whereby annular passages of small cross sectional area are iormedtherebetween. The nozzles 52 communicate with the annular passage 49, which in turn communicates with the space within the fan housing adjacent to the outer periphery of the rotor 38.

The operation of the above described vacuum cleaner is as follows: Rotation of rotor 38 by means of motor 24 causes the rotor to draw air from within inner housing 48 through opening 5| and to eject it at the periphery of the rotor. This immediately reduces the pressure within inner housing 48 and consequently air is drawn from within casing around the dust bag through the induced suction nozzles 53. If, for any of the aforestated reasons, the resistance to air flow through the cleaning nozzle I1 is low, air will pass through the nozzle and hose l6 and through the dust bag |8 in such quantities that it cannot pass through the induced suction nozzles 53 fast enough to balance the reduced pressure within inner housing 48. Consequently, the pressure on the left hand side,,as viewed in Fig; 1, of valve member 42, is greater than that on the other side, and the valve member is opened against the action of spring 46. When the valve member is opened, the pressure diii'erence on either side oi end wall 48 is reduced,,

but the dynamic for e of the air stream passing through opening 4| maintains the valve open. Consequently, most of the air passes through .the large opening 4| and only a small quantity passes through induced suction nozzles 53.

The air discharged from the periphery of rotor 38 passes chiefly to the right, as viewed in Fig. 1, around motor 24, through the openings in wall 28a 01' member 28, through the filter 32 and is discharged through outlet 3||. Under these conditions there is a comparatively large volume of air available for the fan'to circulate and the tan is designed to operate emcientl y' under these conditions.

If the cleaning nozzle i1 is now placed in contact with a 'rug or the like, or ii any other conditions obtain tending to introduce comparatively high resistance into the path of air flow into the cleaner unit, the volume of air drawn into the cleaner unit is correspondingly reduced. This smaller quantity of air does not possess enough dynamic'force' to maintain'the valve member 42 and air passes from the region of higher than atmospheric pressure at the periphery of the rotor through annular passageway 49 and through suction inducing nozzles 52 to the region of this low pressure within housing 48. In passing through the constricted portions of nozzles 52 this air attains a high velocity which produces a Rotor 38 now produces a strong suction effect on the induced suction nozzles 53, whereby air is drawn through nozzles 53 from the space around the dust bag. Nozzles 52 and 53 form jet pumps or ejectors operated by air discharged from the rotor and, when valve member 42 is closed, produce a lower pressure in the space around the dust bag than the fan maintains within housing 48. This lower pressure is very desirable in order to cause flow of air into the cleaning nozzle against the high resistance ofiered by the rug or the like.

The air supplied to nozzles 52 from the discharge of the rotor is recirculated through the rotor and makes up for the small volume of air drawn in through the .nozzle i1 and hence the rotor has about the same volume of air to handle that it had with valve member 42 open. Inasmuch as the rotor is designed to handle this amount of air, it operates more eiliciently than it would with smaller quantities. The air discharged from the rotor and not recirculated passes through the outlet 30 in the same manner as previously-described.

It will be noted that the air recirculated, during periods of small air flow through the cleaning nozzle ll, to make up a sufiicient quantity for efficient operation of the rotor, is gainfully employed to operate the jet pumps to produce a higher degree of vacuum. This higher vacuum is very desirable in order to draw air into the cleaning nozzle against the high resistance to flow offered by the rug or similar article being cleaned, by a hose, or by a small nozzle. During periods of large air flow-through cleaning nozzle H, the pressure is not so low in housing 48 due to the fact that valve member 42 is open, and consequently there is not a large enough pressure drop through the suction inducing nozzles 52 to cause the recirculation of an undesirably large quantity of air.

Under intermediate conditions of resistance to airflow, valve 42 may be partially closed, thus rendering the jet pumps or electors partially eflective.

Fig. 3 shows two curves obtained by plotting the quantity of air flowagainst the vacuum produced. Curve a is that obtained with a vacuum cleaner like that shown in Fig. l, but without. the jet pumps. It will be seen that, as the quantity of air flow is reduced, the vacuum-rises at a comparatively small rate and never reaches a very high value, but at a low vacuum a large volume of air may be circulated. Curve 1), on the other hand, is that obtained with a vacuum cleaner of the type shown in Fig. 1, but with the valve member 42 permanently closed. This curve indicates that there is a very rapid increase in the degree of vacuum produced as the quantity or air flow is reduced, butthat the quantity 01- air which such a device would be capable oi! circulating, even at a very small vacuum, is not large. A high degree of vacuum is desirable when there is a high resistance to the flow of air in orderto draw air into the cleaner unit against this. comparatively high resistance, and hence the performance shown by curve 1) is desirable. On the other hand, a large quantity of air flow is desirable when the nozzle is being used to clean hardwood floors, or whenever the resistance is low, as the largequantity of air drawn into the nozzle picks up more dust than would a smallerquantity and therefore,

. under these conditions, the performance shown by curve a is preferable. Consequently, the spring-AB acting on the valve member 42 is so designed as to close the valve member at the point c where the curves a and b cross. Hence, the curve representing the actual performance of the vacuum cleaner shown in Fig. 1 comprises the parts of the curves 0.. and b shown in full lines. This gives the most efllcient operation for the cleaner under all conditions.

Thevacuum cleaner shown in Fig. 2 operates on the same principle as that shown in Fig. 1, but it embodies several structural differences. The shaft of motor 24 is provided with a fan rotor 60, which is similar to rotor 38 shown in'Fig. 1, having a disc 60a, curved blades 60b and a disc 690, but disc 600 is provided with a conical flange 6| surrounding the inlet opening therein. Rotor 60 is mounted within a fan housing 62. The central part of the forward wall 63 of the housing is formed as an induced suction nozzle. Plate members 65 support a valve housing 66, the forward wall 61 of which is formed with aplurality of openings 68 arranged in a circle about the center thereof. A pin 691s rigidly secured to the center of wall 61 and slidably mounted thereon is a hub 10, which carries a spider 11. Spider 1| carries an annular valve member 12, which serves to close openings 68. A spring 13 is arranged around pin 69 with one end bearing against hub 10 and the other end against a head 14 secured to the pin. Spring 13 tends to maintain the valve member 12 in closed position. The rear wall 15 of valve housing 66 is formed with a cylindrical portion 16 which extends within the induced suction nozzle 64. Supported within the'fan housing 82 by means of plate members 11 is a partition 18, the central part of which is formed as a suction inducing nozzle 19 having a Venturi shaped passage 19a therethrough, and the outer-periphery of which is spaced inwardly from the cylindrical portion of the fan housing. Induced suction nozzle 64 extends into suction inducing nozzle 19.

The conical portion 6| of the rotor disc 69c extends into the annular space formed between nozzle 19 and the remainder of partition 18, as is clearly shown in Fig. 3.

The operation of this embodiment is as follows: If the cleaning nozzle 11 is in contact with a' surface which offers but small resistance to the flow of air, or if other conditions exist'which result in low resistance, the large volume of air drawn in has sufhcient dynamic force to maintain the valve member 12 open against the force of spring 13. Consequently, most of the air passes through openings 68 inthe valve housing 66 and through the cylindrical portion 16 to the central inlet of the rotor 60. The rotor discharges the air at its periphery and most of this air passes to the right, as shown in Fig. 2, to the outlet of the cleaner.

If the resistance to fiow of air into the cleaning nozzle I1 is increased sumciently, the small quantity of air drawn in does not have enough higher vacuum within casing l0 through suction inducing nozzle 19 causes air to be drawn through nozzle 64, thereby producing a arfi und the dust bag than the rotor alone is able to maintain. At the same time, sufiicient air is recirculated so that the fan will operate efliciently.

In the embodiment shown in Fig. 2 the induced suction nozzle 64 corresponds to.the nozzles 53 shown in Fig. 1. Likewise, the suction inducing nozzle 19 in Fig. 2 corresponds to nozzles 52 in the first embodiment.

The performance of the second. embodiment is similar to that of the first, and hence the curves 4 shown in Fig. 3 apply to the second embodiment poses of illustration only and that they are not intended to limit the scope of my invention, which is to be determined only by the appended claims viewed in the light of the prior art.

What I claim is:

1. In a vacuum cleaner having an inlet offering varying resistance to flow of air therethrough, a plurality of suction producing means for inducing flow of air through said inlet, one of said means being a fan and means for increasing the suction efiect of the other suction producing means in response to a decrease in the quantity of airiflowing through said inlet caused by an increase in resistance 'ofiered by the inlet.

2. In a vacuum cleaner having an inlet offering varying resistance to flow of air therethrough, a plurality of suction producing means for in-- ducing flow of air through said inlet including a fan and an ejector, and means for increasing the effect of the ejector in response to a decrease in the quantity of air flowing through said inlet resulting from an increase in resistance oflered by the inlet.

3. In a vacuum cleaner having an inlet, vacuum producing means for causing fiow of air therethrough, said means havinga suction side in communication with said inlet .anda discharge side, means for recirculating air from said discharge side to said suction side, and means operative in response to reduction 'in the flow of air through said inlet to an amount insufficient for eflicient operation of said vacuum producing means to cause flow through the recirculating means.

4. In a vacuum cleaner having an inlet, vacuum producing means for causing fiow of air therethrough, means providing parallel paths .for

the flow of air from said inlet to said vacuum pump for increasing the flow of airthrough the! other of said paths operable by the closing of said closure means.

5. In a vacuum cleaner having an inlet, vac-- uum producing means for causing flow of air therethrough, means provided parallel paths for the flow of air from said inlet to said vacuum producing means, closure means in one of said paths arranged so as to be maintained open by the dynamic force produced by the fiow of a comparatively large quantity of air, and means for increasing the flow of air through the other of said paths, said last mentioned means being operable in response to the closing oi! said closure means upon a reduction in the quantity of air.

6. In a vacuum cleanerhaving an inlet, vacuum producing means for causing flow of air therethrough, means providing parallel paths for the flow or air from said inlet'to said vacuum producing means, movable means in one or said paths responsive to variations in the dynamic force or said air flow, and means for increasing the flow of air through the other of said Paths, said last mentioned means being operable in response to movement oi. said movable means.

7. In a vacuum cleaner having an inlet oiIering varying resistances to the flow of air therethrough, a rotor for inducing flow of air therethrough, an ejector, and means operable under conditions of low resistance to admit large quantities. of air directly to said rotor and operable under conditions of high resistance to cause the air to pass through said ejector before being admitted tosaid rotor so as to increase the vacuum.

produced.

8. In a vacuum cleaner having an inlet oilfering varying resistances to the flow or air therethrough, a rotor for inducing flow of air therehousing and having a motive fluid inlet communicating with the space between said housings, said space communicating with the discharge of said rotor, and an induced suction nozzle extending through the wall of said fan housing and terminating within said suction inducing nozzle and having an inlet in communication with the inlet opening of said casing.

12. In a vacuumcleaner, a casing having an inlet opening, a fan rotor in said casing, a tan housing around said rotor, an inner housing within said fan housing forming a chamber communicating with the inlet of said rotor, a spring pressed inlet valve for said chamber, and a jet pump including a suction inducing nozzle extending through the wall of said inner housing and having a motive fluid inlet communicating with the space between said housings, said space communicating with the discharge of said rotor, and an induced suction nozzle extending through the wall of said fan housing and terminating within said suction inducing nozzle and having through, an ejector between said inlet and said v '-ume of air flow.

rotor, means for supplying air discharged from said rotor as motive fluid for said ejector, and

means operable under conditions of low resistance to admit large quantities oi. air directly to said rotor without passing through said ejector and operable under conditions of high resistance to prevent flow of air directly to said rotor and to increase the effectiveness of saidejec'tor.

9. In a vacuum cleaner ,having an inlet, a rotor iorinducing flow of air therethrough, means forming a chamber communicating with the inlet of said rotor, an inlet valve for said chamber including a spring pressed valve member, and a Jet pump discharging into said chamber, said jet pump having a suction inlet communicating with the first-mentioned inlet.

10. In a vacuum cleaner having an inlet, a rotor for inducing flow of air therethrough, means forming a chamber communicating with the inlet of said rotor, an inlet valve for said chamber including a spring pressed valve member arranged to be maintained open by the dynamic force 01' a large volume or air flow, an ejector discharging into said chamber, said ejector having a suction inlet communicating with the first-mentioned inlet, and means for supply- 5 ing motive fluid to said ejector from the discharge of said rotor.

11. In a vacuum cleaner, a casing having an inlet opening, a fan rotor in said casing, a fan housing around said rotor, an inner housing.

an inlet in communication with the inlet of said casing, the springof said inlet valve havin strength suflicient to maintain said valve closed under conditions of comparatively small air flow while permitting it to be maintained open by the dynamic force of a comparatively large vol-.

with said suction inducing nozzle, said induced suction nozz le extending within said suction inducing nozzle, means forming a chamber having an outlet extending within-said nozzles, and a spring pressed'inlet valve for preventing flow of air into said chamber.

14. In a vacuum cleaner, a casing having an inlet, a fan rotor in said casing, "a fan housing around said rotor, said housing having an inlet formed as an induced suction nozzle, a partition within said housing having a central opening formed as a suction inducing nozzle, said partition forming with said housing a passage communicating with the discharge of said rotor and with said suction inducing nozzle, said induced suction nozzle extending within said suction inducing nozzle, means forming a chamber having an outlet extending within said nozzles, and a spring pressed inlet valve for preventing flow oi air'into said chamber, the spring of said inlet valve having strength suflicient to maintain said valve closed under conditions of comparatively small air flow while permitting it to be maintained open by the dynamic force of a comparatively large volume of air flow.

JAN CARL CLASON. 

